1. Field of the Invention
The disclosure relates generally to dental instruments and, more specifically, to prophy angles and adapters for use with prophy angles.
2. Description of the Related Art
Dental prophylaxis angles, generally referred to as “prophy angles,” are commonly used dental instruments for providing rotation for dental tools such as brushes, prophy cups, or other receptacles used in cleaning/polishing teeth. Referring to FIGS. 1A and 1B, a prophy angle 10 can include an inner housing 16 having an outer housing 18 and a rotor 14 extending at approximately a 90° angle to the neck 18, which increases the ability of a dentist to reach various surfaces of the teeth of a patient. A drive shaft or rotating member 12 can be located within the housing 16 and attached to a driven gear 20 in the head of the prophy angle. Prophy angles 10 are generally affixed to an adapter or hand piece (not shown), which connects the prophy angle to a drive source (not shown), thereby enabling a rotating motion of the rotating member 12 and driven gear 20 of the prophy angle and any affixed dental tool.
Prophy angles 10 are commonly manufactured from lightweight plastic to make them disposable, thereby increasing overall sterility in the dental environment. Being disposable, there is a desire to reduce the cost and/or complexity of assembly of the prophy angle 10 while, at the same time, maintaining the functionality and safety of the prophy angle 10.
One technique to reduce cost is to limit the number of separate pieces in the assembly of the prophy angle 10. For example, the prophy angle in FIG. 1B includes four separate pieces: (i) the rotating member 12, (ii) the inner housing 16, (iii) the outer housing 18, (iv) and the rotor 14. A reduced number of separate pieces requires less molds to form the separate pieces and less assembly of the pieces. However, by reducing the numbers of separate pieces, each individual and separate piece typically becomes more complex as each piece can take on more functions.
One of the issues preventing further reduction in the number of pieces in a disposable prophy angle 10 relates to the ability of the prophy angle 10 to maintain and restrain the position of the rotor 14 within the outer housing 16. Since the rotor 14 both engages the rotating member 12 and rotates at a head speed, the position of the rotor 14 within the outer housing 16 is critical to maintain a proper engagement between the rotating member and the rotor 14 and to prevent the rotor 14 from being unbalanced during rotation. An improperly positioned and/or restrained rotor 14 can cause failure of the prophy angle 10 and/or causes damage to the adaptor, the dental professional and/or the patient. There is, therefore, a need for an improved prophy angle that reduces the number of pieces in the prophy angle yet while maintaining the positional stability of the rotor within the outer housing.